Loadbreak devices for housed cutouts



sept', 22, 1959 R. H. EARLE LOADBREAK DEVICES FOR HOUSD CUTOUTS FiledJune 16, 1958 2 Sheets-Sheet 1 Itiiin mvafvoa RALPH H. Emme BY EJO fATTRHELY Sept. 22, 1959 R. H. EARLE LOADBREAK DEVICES FOR HoUsEDcu'roUTs 2 Sheets-Sheet 2 Filed June 16, 1958 mvEHToR RALPH H. EARLS ai; W(

ATToRNeY l. LOADBREK' DEVICESVQFOR HOUSED Y('JUTOUTS W'RalphL H.Eai-le,` Wauwatosa, Wis., assgnor to I`McGraw- Edison Company,-Milwaukee, Wis., .a corporation of nDelaware 'A This. invention`relates to 1oadbre'ak.devicesf forlhoused jfcutouts.

Y'In vcertain loadbreak devices forlvhoused .cutouts, as .fheretoforeconstructed, fthefloadbreak'device lis mounted vLin-.su'cha manner 'thatit"dischar'gesin the direction of lthe opertaor when he opens the 'doorof .the housed cut- .outthus endangering the 'safety of the operator.

Further .than this, inloadbreak devices of thisgeneral type it has'been`necessary to make ,specialhousings and to Changes otherparts of Vthedevicefso that al standard type of cutout could notibe used withthe.loadbreak de- ;vice itself.

y'This invention isdesigned to overcome the above noted idefectsandlanobject of this invention is to provide a `lloadbreak devicewhich is soconstructed that it may l-`:be used with `a standard housed' cutoutwithout'requiring `:any change whatsoever in the' main body ofthehousing, ;and only requiring a special door whichmay be sub- :stitutedfor the usual or conventional door of Ythehoused l'cutout. f In housed'fuse cutouts itis the usual'practice'tojprovide'a porcelain -housing`or other type of ceramic I@housing and'to provide a Bakelite orotheritypeof plasticremovable door, and"ther'efore this' invention may'l-be readily applied to"such'construction inthat the 4con- 'vent'ionaldoor may be removed and replaced by the new door with'theloadbreakdevice.

A further and specific Vobject ot'fthisinvention is to "jprovide aconstruction of loadbreakdevice'for any of the nlsual'types of housedcutouts such as housed drop-out fuses forexample, which is somadethatthe door may readily be substituted for the conventional "door of ahoused fuse or for -other types ofV cutout while still retain-`viingall'o'f theusual advantages of the conventional cut- `out.

.A'further object is to provide-adoor construction for a 'housed -fusecutout' in lwhich the loadbreak device is hformed asa unitary portion oftheidoor so that theidoor v4'may `be opened Vunder load by hand or-by-aswitch stick "and to Aso construct'and fposition thelloadbreak v'device"that the blast'ffrom it is directed raway from the face of theoperatorwvhen he opens the door under load.

A further object -is--to provide a construction whichis eminentlypractical vand which-V may be easily made Vand which has -ayminimurnvnumber ofy par-ts all offwhi'ch are 'wsturdyf and reliable.

Embodiments of the invention-are Ashown inz the accompanying drawings,inwhich:

Figure 1 is ase`ction'a1' view'showing vafhoused fuse cutout-Withthedoorin closed position.

Figure 2 s-a fragmentary sectional view showing the door in lpartiallyopen position.

fit-willbe seenthat the device Vis adapted tobe used withan-ordinarytype of housed cutout.

"The lhousedfcutout is yprovided' within: a\.-l1ousing 1,

""iisually of porcelain, -which has-upper andelower. `contacts cthebrassrod 25. VThe rear end ofthe .Lucite,plunger 1-.26..isprovided with arigidly, attached, co1lar..27 ,ff-.which icc indicatedgenerally by Athereference characters'land. The housing isadapted-.toremovably receivethe ordinary Bakelite or plastic door, not shown, and the presentinvention provides a special `door '4 .which replaces the ordinarydoorffor the common type of housed cutouts.

The Adoor 4'carries afuse tube which may beslidably or otherwisesupportedfrom 'the door. The. fusestructure indicated generally by V`thereference character 5,

Vincludes* thefusef tube 6. EThefuse tube`6 may be of theusualtypeexceptfor thev special metallic cap or top` portion 7. "The cap7 isscrewedon theV tubeV 6 in the usual manner and is provided with acylindrical portion .8 of reduced diameter. p A

The door' 4 is provided' withfthe usual eyeletor member 9 which isadapted to receive the inger'of an operator or `a switchl stickso thatAit may vbemanuallyjopene'd ,or closed Iwhen desired.

Thisinventionis designed to `provide a special form #of door which'has-a' loadbreakdevice forming aportion thereofvand' so constructedthatithe door may bev pulled open while the housed.` cutout is carryingva load, without damage-tOfthe'uppercontacts kof either the housing orfuse tube, since the separation or break in the circuit Voccurs=withina-cylindricahportion` of the special door'ft.

This cylindrical extension' or portion 10 is provided with a lfiber tube11 Vwhich is screwed into an arcing v"electrode-12,:carried within thetubular portionl. The tubular portion-10? is "providedv'withfan'enlargedcylindrical chamber 13 andwith -a'srnaller cylindrical chamber 14.'Theiberftubef 11 is positioned within the tubular portionl() of'the-loa'db-reak device, land is providedwith afscrewthreadedportionil-S which, as stated above, is

screwed Iinto the arcing contact orI `electrode112. vThe.arcingelectrode12-mayfbe of brassor other conducting imaterial.'Ihearcing electrode 12 is removably carried withinthe intermediateportion 16-and is held in place electrode 12 inzplace. `Between the nut17 and the elecnletallic toporcap`7vof the'fusev tube6 and is aperturedas indicatedat Z1 and fits over yor receives the reduced cylindricalextension??? formednintegrally with the cap 7. The iingerZtl alsoactsasa means for withdrawing or rocking the fuseV tubeY structure when thedoor is opened as it pulls directlypagainst the top` cap of the fusetube and carries the fusewtubeoutwardly when the door is rockedoutwardly.

'The upper stationary contact 2 ofthev housing is pro- -vided with aU-shaped spring nger122 whosev lower portion is bent rearwardly, -Kasshown,l and directly .con-

tacts ytheV top of the .reduced portion 8 of the metal cap 7 of the fuse`tube under normal conditions.

Analnicmmagnet or Contact ,member 23 is removablyclipped or fastened -tothe. stationary upper contact of the housing by anysuitable means `asfor example the clip 24 so that it maybe added `to a conventional.housed fuse structure by merely clipping it on to the upper contact ofthe housing.

,One of thetmain portions, of the loadbreak device in- `cludes the-slidable plunger formed of the conducting `metal yrod or plungerportion'25 which may beof brass or other suitable material, .and `therearward or outward extension 26 of suitable insulating-material such asLucite for example. This Lucite plunger 26 is secured inanysuitablemanner to the outer or rear end of 3 may be of metal or may beformed of plastic as an integral portion of the plunger 26.

The composite plunger 25, 26 is provided with an alnico magnetic roundedterminal or magnetic contact portion 28 which engages the magneticmember`23 and thus holds the slidable -rod or slidable plunger 25, 26 inplace under normal conditions and with the magnetic portions 23 and 28in contact with each other thus forming a conducting path for thecurrent from the upper stationary contact 2 of the housing through thebrass rod portion 25 of the plunger to the arcing Contact 12 of theloadbreak device and from there to the spring finger or contact iinger20 which engages the upper metal cap of the fuse tube. the door isclosed-or in other words when the device is in normal operative positionthere are two paths arranged in shunt or parallel; one of them from theupper contact directly to the upper cap 7 of the fuse tube and the otherfrom the upper contact 2 of the housing through the contact members ormagnetic portions 23 and 28 through the brass rod 25, through the finger20 to the upper metal cap 7 of the fuse tube. The current It will beseen therefore that when I then flows through the fuse link, not shown,to the lower stationary contact of the housing.

The operation of the apparatus is as follows: When it is desired to openthe circuit under load it is merely necessary for the operator to pullthe door ouen bv engaging the 'iinger or eyelet 9 of the door with hisfinger supporting structure 29. This outward motion of the doorcontinues with the two parallel or shunt circuits both intact asdescribed hereinabove, until the upper contact or movable contact 7 ofthe fuse tube passes beyond engagement with the upper stationary contactiinger 22 of the upper stationary contact 2 of the housing.

However, continued rocking of the door outwardly, causes the contact rod25 of the composite plunger 25, 26 to pass beyond or out of contact withthe arcing contact or electrode 12. At this time the circuit is brokenwithin the tubular portion 10 and this interruption pro duces an arcwhich immediately causes the cylindrical portion 14 to be filled withpressure gas. This increases the outward speed of the rod 25 of theplunger rod 25, 26 with reference to the cylindrical portion 10 of thedoor. The arc is quickly extinguished due to the pressure gas in thechamber 14 and also due to the outward blast of the gas past the arcingelectrode.

The composite plunger rod 25, 26 has a loose tit with the cylindricaltubular sleeve or member 11 and the gas is free to pass through thisrestricted area between the rod and the iiber tube 11. If desired thetubular portion 14 may be provided with a vent or vents to preventexcessive pressure being built up so as to guard against bursting of thetubular cylindrical portion 14. The vents are not shown in the iigures.

The relative motion of the composite rod 25, 26 with respect to the doorcontinues until the shoulder or iiange 27 abuts the arcing contact 12and arrests further outward motion of the composite plunger or rod 25,26 with reference to the tubular member 10.

When the device is put back into operation and the door closed, it is tobe noted that the composite rod 25, 26 will drop backward, or in otherwords downward, into the tubular member 10 to its initial position. lfdesired a spring may be provided to assist in retractingA orrepositioning the composite rod 25, 26. The spring is shown at 31 inFigure 3. The spring 31 is partly housed within a recessed portion 32 ofthe Lucite plunger 26 and partly housed within a recessed portion of theextension 33 of the tubular member 10. The ends of the spring may befastened to the Lucite rod 26' and to l 4 the extension 33 in anysuitable manner for example by means of transverse pins.

It is to be understood that either one or both of the members 23 and 28may 4be formed of alnico magnetic' material and the other of soft iron.

It is further to be understood that minor changes may be made in thestructure of the loadbreak device without departing from the spirit ofthis invention. Therefore, although the invention has' been described inconsiderable detail it is to be understood that such' description isintended as illustrative and not as limiting, as the invention may bevariously embodied and-is to be interpreted as claimed.

I claim: v

1. A loadbreak device comprisinga housing, a door pivoted at the lowerportion thereof on said housing, said housing having contacts includingan upper stationary contact, a fuse tube supported from said door andmovable outwardly as a unit with said door when said door is rockedoutwardly, said fuse tube having an upper contact cap normally incontact with the upper stationary contact of said housing, a load-breakdevice carried as a unitary portion with said door and having acylindrical portion' provided with an open discharge end directedinwardly of the housing and away from the front of the door, a compositeplunger slidable in said cylindrical portion and having an outer portionof insulating material and an inner portion of metal, the upperstationary contact of said housing and the outer end of the metalportion of said plunger having magnetic members normally in contact witheach other, at least one of said magnetic members being a permanentmagnet, and one of said magnetic members having a rounded face incontact with the opposed face of the other magnetic member whereby whensaid door is rocked outwardly, the rounded face of one of said magneticmembers will roll upon the face of the other magnetic member as theangularity of the door with reference to the housing changes due to itsrocking outward motion, said loadbreak device including a xed contact inthe cylindrical portion, and connecting means electrically joining themetallic portion of said composite plunger to the upper conducting capof said fuse tube, whereby when said door is rocked outwardly beyond apredetermined point the upper metal cap of the fuse tube passes out ofcontact with the stationary upper contact of said housing and thereafterthe metallic portion of the composite plunger passes out of contact withthe fixed contact of the loadbreak device.

2. A loadbreak device comprising a housing having contacts one of whichis an upper stationary contact, a removable magnetic member detachablycarried by the upper stationary contact, said magnetic member havingattraction only and acting solely as a temporary holding magnet, a doorpivoted on said housing and rockable outwardly therefrom, a fuse tubecarried by said door and having an upper contact normally in contactwith the upper stationary contact of said housing, a loadbreak devicecarriedv as a unitary portion of said door and bridged between saidupper stationary contact and the upper contact of said fuse tube, saidloadbreak device being positioned to open after the upper contact of`said fuse tube has moved away from the upper stationary contact of saidhousing.

3. A loadbreak device comprising a housing having a stationary uppercontact, a door pivotally mounted on said housing, a fuse tube carriedas a unitary portion of said door and having an upper contact normallyin engagement with the upper stationary Contact, a loadbreak devicecarried as a unitary portion of said door and rockable outwardly as aunit with said door, said loadbreak device being connected in shuntbetween the upper stationary contact and the upper contact of said fusetube and arranged to open the circuit after the upper contact of thefuse tube has moved away from the upper stationary contact, saidloadbreak device including a movable actuating member, a removablemagnetic member detachably carried by the upper stationary contact ofsaid housing, the movable actuating member having a magnetic membernormally in engagement with the removable magnetic member carried by theupper stationary contact, both of the magnetic members having attractiononly, at least one of said magnetic members being a permanent magnet.

4. A loadbreak device comprising a housing having a stationary uppercontact, a door pivotally mounted on said housing, a fuse tube carriedas a unitary portion of said door and having an upper contact normallyin engagement with the upper stationary contact, a loadbreak devicecarried as a unitary portion of said door and rockable outwardly as aunit with said door, said loadbreak device being connected in shuntbetween the upper stationary contact and the upper contact of said fusetube and arranged to open the circuit after the upper Contact of thefuse tube has moved away from the upper stationary contact, saidloadbreak device including a movable actuating member, a removablemagnetic member detachably carried by the upper stationary contact ofsaid housing, the movable actuating member having a magnetic membernormally in engagement with the removable magnetic member carried by theupper stationary contact, at least one of said magnetic members being apermanent magnet, one of said magnetic members having a flat face andthe other of said magnetic members having a rounded face normally incontact with said flat face to accommodate the angular shifting of themovable portion of said loadbreak device as the door is rocked outwardlyto open position.

References Cited in the file of this patent UNITED STATES PATENTS MikosFeb. 18, 1958

